Fourth generation (4G) cellular networks employing newer radio access technology (RAT) systems that implement the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) and LTE Advanced (LTE-A) standards are rapidly being developed and deployed within the United States and abroad. LTE-A brings with it the aggregation of multiple component carriers (CCs) to enable this wireless communications standard to meet the bandwidth requirements of multi-carrier systems that cumulatively achieve data rates not possible by predecessor LTE versions.
Efficient and seamless mobility control is an important objective for continued LTE and LTE-A system development. Unfortunately, in some LTE network deployments, user equipment (UE) mobility can be negatively impacted by different handover and device power saving mechanisms that are being employed by network service providers during certain network cell handover procedures. For instance, for some device applications, relatively short data communication interruptions may be tolerable (e.g., for applications that download large data files over the Internet), whereas, for other latency-sensitive device applications (e.g., for voice over LTE, VoLTE, or streaming video applications) even short, untimely interruptions in data communications can negatively affect a user's experience.
By way of example, when a single radio LTE (SRLTE) device, such as a UE that is not capable of performing simultaneous LTE data communications alongside legacy network (e.g., CDMA2000 1×) voice call communications, transitions from a coverage area of its serving network base station (e.g., an enhanced NodeB or eNodeB) into a new coverage area associated with a neighbor network base station, the UE can detect (e.g., by periodically measuring specific radio signals) when a received radio power associated with its serving network base station is fading (e.g., due to path loss), at the same time that a received radio power associated with the neighbor network base station is increasing.
In response to detecting this development, the UE can initiate a handover procedure from its serving network base station to a neighbor network base station that is determined to have a stronger radio signal, e.g., from the perspective of the UE. However, in certain situations, this handover attempt may be unsuccessful due to auxiliary communication processes that can interrupt the handover attempt and cause the handover to fail. In circumstances where the handover attempt fails, the UE can be configured to reattach to its serving network base station by default (e.g., in an effort to save device battery power), to rapidly resume communications with a known cell base station.
However, this default reattachment procedure can be detrimental for the UE as its serving network base station may not be capable of providing the UE with reliable, high-throughput communications service at the UE's present location (e.g., as the UE has already substantially roamed away from the coverage area of its serving network base station). For a period of time after this questionable reattachment, any subsequent communications service requests emanating from the UE will be handled by the serving network base station, until a separate network cell reselection procedure is carried out, e.g., after the expiration of a discontinuous reception mode (DRX) timer. During this time the UE must communicate within a cell edge region of its serving cell. As such, a user of the UE will experience degraded device performance that can be associated with delayed, fluctuating, and/or lost data communications.
In this situation, when the UE attempts to transfer or stream data via the Internet, the data may not be presented correctly, or in a timely manner, on a display of the UE. Further, some UEs may be configured to repeatedly attempt to retransmit the same service request to their serving network base station in situations where one or more previous service requests fail due to path loss and increased interference. As a result of these service request retries, network cell re-selection of a better performing neighbor base station can be detrimentally delayed.
Accordingly, there exists a need for a solution that can improve UE device mobility in response to failed handover attempts. LTE network deployments can benefit from this dynamic mobility control when it is employed in conjunction with various network cell handover procedures and/or various network cell reselection procedures.